Investigation of the condensation and freezing behavior of freely suspended supercooled molecular gases and particles in the nano to millimeter size range

研究纳米至毫米尺寸范围内悬浮的过冷分子气体和颗粒的冷凝和冻结行为

• 批准号: 189900837
• 负责人: Professor Dr. Sigurd Bauerecker
• 金额: --
• 依托单位: Institut für Physikalische und Theoretische Chemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2011
• 资助国家: 德国
• 起止时间: 2010-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/189900837?language=en
• 关键词: Investigation; condensation; freezing; behavior; freely

In the project supercooled molecules as well as nano, micro and millimeter droplets shall be investigated with respect to their condensation, aggregation and freezing behavior in a gaseous vicinity. For this purpose, optical methods as high resolution infrared spectroscopy, Raman spectroscopy, terahertz spectroscopy (by use of synchrotron sources), and high-speed filming will be applied. Theoretical support will especially be delivered by collaborators through computer simulations. From our group finite element methods for the investigation of heat production and distribution during freezing as well as the discrete dipole approximation method for optical particle characterization will be used. One main focus will be a new, improved collisional cooling system which shall be developed for cooling, supercooling and spectroscopy of molecular gases, nano and micro aerosols in the temperature region of 4 to 400 K. For this system our experiences of the last 15 years with the old well-tried system will be considered as well as other technical improvements. As a key technology a more powerful sample-gas inlet system for supercooling of gases shall be constructed. Performing high resolution spectroscopy of supercooled gases we aim at an improved understanding of the intra-molecular dynamics via global potential hyper-surfaces. Highly qualitative measuring data shall be delivered for data bases as HITRAN or GEISHA under consideration of applications, e.g., in environmental sciences. Concerning aerosols, water and other substances stand in the focus as they are important for the physical chemistry of the atmospheres of the Earth and other planets and their satellites and also for interstellar gases. Especially the freezing behavior of microdroplets within an aerosol cloud shall be unraveled (concerning dynamics, size-, shape-, phase-, and structure-evolution, heat production and transport, optical constants); last but not least for the interpretation of Raman lidar data. Concerning freely suspended droplets from water and aqueous solutions in the millimeter size range, the first rapid freezing stage which passes in milliseconds shall be investigated and characterized as well as the evolving dendritic network ice. During the first project stage we observed an electric effect showing freezing potentials of up to 6 V. This effect shall be unraveled now. The influence of the asymmetric network structure of the dendritic ice on the ion distribution within the final ice shall be explained, especially the impact on the particle chemistry and electric potential generation in thunderclouds. Furthermore, we will study the analogy of the formation of regular dendritic ice to the formation of snowflakes in air, as well as the transition towards smaller particles in the micrometer size range.

在项目中，超冷分子以及纳米，微滴和毫米液滴应在气态附近的凝结，聚集和冻结行为方面进行研究。为此，将应用光学方法作为高分辨率红外光谱，拉曼光谱，Terahertz光谱（通过使用同步源源）和高速拍摄。合作者将特别通过计算机模拟提供理论支持。从我们的组有限元方法中，将使用用于冻结过程中的热量产生和分布以及光学粒子表征的离散偶极近似方法的研究。一个主要的重点将是一种新的，改进的碰撞冷却系统，该系统应用于在4至400 K的温度区域的分子气，纳米和微气溶胶的冷却，过冷和光谱。对于这一系统，我们将考虑到过去15年的旧良好训练系统的经验以及其他技术改进。作为关键技术，应构建一种更强大的样品气体入口系统，用于过冷气体冷却。对超冷气体进行高分辨率光谱，我们旨在通过全球潜在的高表面表面提高对分子内动力学的了解。应为数据库（例如，在环境科学中考虑应用程序中的Hitran或Geisha）提供高度定性的测量数据。关于气溶胶，水和其他物质的关注点，因为它们对于地球和其他行星及其卫星以及星际气体的物理化学很重要。尤其是气溶胶云中微词的冰冻行为应被揭开（涉及动态，尺寸，形状，相位和结构进化，热量产生和传输，光学常数）；最后但并非最不重要的是解释拉曼激光雷达数据。关于在毫米尺寸范围内从水和水溶液中自由悬浮的液滴，应研究和表征第一个以毫秒为单位的快速冷冻阶段，以及不断发展的树突状冰冰。在第一个项目阶段，我们观察到电效应显示最多6 V的冻结电势。应解释树突状冰的不对称网络结构对最终冰中离子分布的影响，尤其是对雷云中粒子化学和电势产生的影响。此外，我们将研究常规树突冰与空气中雪花形成的形成，以及在微米尺寸范围内向较小颗粒的过渡。

项目成果

Study of the high resolution spectrum of (SOO)-S-32-O-16-O-18: The nu(1) and nu(3) bands

(SOO)-S-32-O-16-O-18 的高分辨率光谱研究：nu(1) 和 nu(3) 波段

• DOI: 10.1016/j.jqsrt.2015.08.010
• 发表时间: 2016
• 期刊: Journal of Quantitative Spectroscopy & Radiative Transfer
• 影响因子: 2.3
• 作者: O.N. Ulenikov;E.S. Bekhtereva;Yu.V. Krivchikova;V.A. Zamotaeva;T. Buttersack;C. Sydow;S. Bauerecker
• 通讯作者: S. Bauerecker